City using data to draft a plan on nutrient loading in the Sanibel Slough

December 12, 2013

The City of Sanibel continues to collect data and develop a plan to decrease the nutrient loads in the Sanibel Slough.

The meandering waterway has higher than normal levels of nitrogen and phosphorous, which the city and local environmental officials have been working together to counteract with new, data-based practices.

"What we're working on here on the island, which we've been doing for several years, is to address the water quality issues," said Sanibel Natural Resources Director James Evans. "The water quality in that slough is relatively low and we're trying to improve that water quality."

Mark Thompson, a biologist with the Sanibel Captiva Conservation Foundation, reported to city council that there is a high concentration of nutrients in the slough that aren't affected by the plume that comes down the Caloosahatchee River. Instead, a majority of these nutrients come from residential fertilizers and reclaimed water for irrigation.

The city's Natural Resources Department reported it's now in the first phase of its Comprehensive Nutrient Reduction Plan, said Evans.

"The idea was to gather all of that data in one place, analyze that data, and look at modeling for nutrient hot spots," he said. "And, once we did that, to develop a plan on where we may have some data gaps to see what additional monitoring may be required, and develop a plan on how to fill those gaps. Finally, we will fill those data gaps, go back, and implement best management practices."

The collected data goes as far back as the 1970's from the City of Sanibel, SCCF, and Lee County.

During his report to city council, Thompson pointed out that Sanibel's 2007 fertilizer ordinance and partnerships with island golf courses to keep nutrients out of local water bodies has been improving overall water quality. Additional nutrient loading has also been curbed by eliminating septic systems and strategic environmental planning, he said.

City Council Member Mick Denham said the fertilizer ordinance has shown some benefits to what the city has done. He said the city also needs to look into cleaning nutrients out of its reclaimed water.

The Sanibel slough was determined to be impaired for nutrients by the Florida Department of Environmental Protection and Evans said the city is trying to get ahead of the state by addressing the water quality issues now.

"We're trying to get ahead of the DEP and address our water quality concerns rather than waiting for them to implement a plan," said Evans. " Sanibel has always been a leader in water quality."